As Jalopnik photographer-of-the-star-cars Curtis Walker was want to tell us — there are rules for booth babes at SEMA. Apparently, this stuff doesn't just happen by chance — and here's his explanation of where you'll find the booth babes, what they'll be wearing and why — and all with a helpful reference gallery below:

"It would appear that there is a correlation between skin factor and company size. Ford and GM, for example, don't have booth babes. Companies selling rims and exhaust systems have girls with cleavage showing in the front or rear."

While we'd agree with Curtis' assessment, we feel compelled to add the following addendum:

"Companies selling tires have girls with cleavage showing in the front and the rear."

Because you know, that's just how they roll — we mean, how else are you going to get folks to snap pictures of your tires? – Ray Wert